1. Field of the Invention
The present invention relates to crystalline sodium paraformylphenolate, to the process for its industrial production from glyoxylic acid and to its use.
It relates in particular, by way of novel industrial product, to sodium paraformylphenolate crystallised with two molecules of water.
2. Description of the Prior Art
In the Prior Art, sodium paraformylphenolate is a derivative of parahydroxybenzaldehyde widely used, either to obtain parahydroxybenzaldehyde, or to prepare various paraalkoxybenzaldehydes, or lastly to carry out various condensations involving the aldehydic carbonyl group.
However, in these reactions, sodium paraformylphenolate is only an intermediate not isolated in the pure crystalline state.
To Applicant's knowledge, it was isolated intermediately by ISTVAN SIMONYI and Coll., Magyar Kem. Folyoirat 62, 76-9 (1956). These authors prepared and recrystallised this product in water before converting it into parahydroxybenzaldehyde by 20% of sulfuric acid in water, but they neither determined its physical characteristics, nor obtained this product crystallised with two molecules of water, in the pure state enabling recourse to the subsequent purification steps of the resulting parahydroxybenzaldehyde to be dispensed with.
In the same way, it is to be noted that sodium paraformylphenolate has never been isolated in the pure crystalline state with two molecules of water, although it is abundantly used, particularly in aqueous solution. In solution in the latter solvent, L. A. COHEN, J. Org. Chem. 22, 1333-5 (1957) determined its ultraviolet absorption spectrum: max 330 nm log.epsilon.=3.9.
K. K. SATPATHY and Coll., J. Indian Chem. Soc. 49, 615-20 (1972) investigated the behaviour of 3-nitro 4-chloro benzaldehyde with respect to dry sodium paraformylphenolate obtained by treating pure parahydroxybenzaldehyde with the stoichiometric amount of sodium ethylate in ethanol, then by filtering it, and drying to constant weight at 100.degree.-110.degree. C., the precipitate obtained; but no physical constant was given.